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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Copyright (C) 2006 The Guava Authors<a name="line.2"></a>
<span class="sourceLineNo">003</span> *<a name="line.3"></a>
<span class="sourceLineNo">004</span> * Licensed under the Apache License, Version 2.0 (the "License");<a name="line.4"></a>
<span class="sourceLineNo">005</span> * you may not use this file except in compliance with the License.<a name="line.5"></a>
<span class="sourceLineNo">006</span> * You may obtain a copy of the License at<a name="line.6"></a>
<span class="sourceLineNo">007</span> *<a name="line.7"></a>
<span class="sourceLineNo">008</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * Unless required by applicable law or agreed to in writing, software<a name="line.10"></a>
<span class="sourceLineNo">011</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.11"></a>
<span class="sourceLineNo">012</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.12"></a>
<span class="sourceLineNo">013</span> * See the License for the specific language governing permissions and<a name="line.13"></a>
<span class="sourceLineNo">014</span> * limitations under the License.<a name="line.14"></a>
<span class="sourceLineNo">015</span> */<a name="line.15"></a>
<span class="sourceLineNo">016</span><a name="line.16"></a>
<span class="sourceLineNo">017</span>package com.google.common.util.concurrent;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>import static com.google.common.base.Preconditions.checkArgument;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import static com.google.common.base.Preconditions.checkNotNull;<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>import com.google.common.annotations.Beta;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import com.google.common.collect.ObjectArrays;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import com.google.common.collect.Sets;<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>import java.lang.reflect.InvocationHandler;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import java.lang.reflect.InvocationTargetException;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import java.lang.reflect.Method;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import java.lang.reflect.Proxy;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import java.util.Set;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import java.util.concurrent.Callable;<a name="line.31"></a>
<span class="sourceLineNo">032</span>import java.util.concurrent.ExecutionException;<a name="line.32"></a>
<span class="sourceLineNo">033</span>import java.util.concurrent.ExecutorService;<a name="line.33"></a>
<span class="sourceLineNo">034</span>import java.util.concurrent.Executors;<a name="line.34"></a>
<span class="sourceLineNo">035</span>import java.util.concurrent.Future;<a name="line.35"></a>
<span class="sourceLineNo">036</span>import java.util.concurrent.TimeUnit;<a name="line.36"></a>
<span class="sourceLineNo">037</span>import java.util.concurrent.TimeoutException;<a name="line.37"></a>
<span class="sourceLineNo">038</span><a name="line.38"></a>
<span class="sourceLineNo">039</span>/**<a name="line.39"></a>
<span class="sourceLineNo">040</span> * A TimeLimiter that runs method calls in the background using an<a name="line.40"></a>
<span class="sourceLineNo">041</span> * {@link ExecutorService}.  If the time limit expires for a given method call,<a name="line.41"></a>
<span class="sourceLineNo">042</span> * the thread running the call will be interrupted.<a name="line.42"></a>
<span class="sourceLineNo">043</span> *<a name="line.43"></a>
<span class="sourceLineNo">044</span> * @author Kevin Bourrillion<a name="line.44"></a>
<span class="sourceLineNo">045</span> * @since 1.0<a name="line.45"></a>
<span class="sourceLineNo">046</span> */<a name="line.46"></a>
<span class="sourceLineNo">047</span>@Beta<a name="line.47"></a>
<span class="sourceLineNo">048</span>public final class SimpleTimeLimiter implements TimeLimiter {<a name="line.48"></a>
<span class="sourceLineNo">049</span><a name="line.49"></a>
<span class="sourceLineNo">050</span>  private final ExecutorService executor;<a name="line.50"></a>
<span class="sourceLineNo">051</span><a name="line.51"></a>
<span class="sourceLineNo">052</span>  /**<a name="line.52"></a>
<span class="sourceLineNo">053</span>   * Constructs a TimeLimiter instance using the given executor service to<a name="line.53"></a>
<span class="sourceLineNo">054</span>   * execute proxied method calls.<a name="line.54"></a>
<span class="sourceLineNo">055</span>   * &lt;p&gt;<a name="line.55"></a>
<span class="sourceLineNo">056</span>   * &lt;b&gt;Warning:&lt;/b&gt; using a bounded executor<a name="line.56"></a>
<span class="sourceLineNo">057</span>   * may be counterproductive!  If the thread pool fills up, any time callers<a name="line.57"></a>
<span class="sourceLineNo">058</span>   * spend waiting for a thread may count toward their time limit, and in<a name="line.58"></a>
<span class="sourceLineNo">059</span>   * this case the call may even time out before the target method is ever<a name="line.59"></a>
<span class="sourceLineNo">060</span>   * invoked.<a name="line.60"></a>
<span class="sourceLineNo">061</span>   *<a name="line.61"></a>
<span class="sourceLineNo">062</span>   * @param executor the ExecutorService that will execute the method calls on<a name="line.62"></a>
<span class="sourceLineNo">063</span>   *     the target objects; for example, a {@link<a name="line.63"></a>
<span class="sourceLineNo">064</span>   *     Executors#newCachedThreadPool()}.<a name="line.64"></a>
<span class="sourceLineNo">065</span>   */<a name="line.65"></a>
<span class="sourceLineNo">066</span>  public SimpleTimeLimiter(ExecutorService executor) {<a name="line.66"></a>
<span class="sourceLineNo">067</span>    this.executor = checkNotNull(executor);<a name="line.67"></a>
<span class="sourceLineNo">068</span>  }<a name="line.68"></a>
<span class="sourceLineNo">069</span><a name="line.69"></a>
<span class="sourceLineNo">070</span>  /**<a name="line.70"></a>
<span class="sourceLineNo">071</span>   * Constructs a TimeLimiter instance using a {@link<a name="line.71"></a>
<span class="sourceLineNo">072</span>   * Executors#newCachedThreadPool()} to execute proxied method calls.<a name="line.72"></a>
<span class="sourceLineNo">073</span>   *<a name="line.73"></a>
<span class="sourceLineNo">074</span>   * &lt;p&gt;&lt;b&gt;Warning:&lt;/b&gt; using a bounded executor may be counterproductive! If<a name="line.74"></a>
<span class="sourceLineNo">075</span>   * the thread pool fills up, any time callers spend waiting for a thread may<a name="line.75"></a>
<span class="sourceLineNo">076</span>   * count toward their time limit, and in this case the call may even time out<a name="line.76"></a>
<span class="sourceLineNo">077</span>   * before the target method is ever invoked.<a name="line.77"></a>
<span class="sourceLineNo">078</span>   */<a name="line.78"></a>
<span class="sourceLineNo">079</span>  public SimpleTimeLimiter() {<a name="line.79"></a>
<span class="sourceLineNo">080</span>    this(Executors.newCachedThreadPool());<a name="line.80"></a>
<span class="sourceLineNo">081</span>  }<a name="line.81"></a>
<span class="sourceLineNo">082</span><a name="line.82"></a>
<span class="sourceLineNo">083</span>  @Override<a name="line.83"></a>
<span class="sourceLineNo">084</span>  public &lt;T&gt; T newProxy(final T target, Class&lt;T&gt; interfaceType,<a name="line.84"></a>
<span class="sourceLineNo">085</span>      final long timeoutDuration, final TimeUnit timeoutUnit) {<a name="line.85"></a>
<span class="sourceLineNo">086</span>    checkNotNull(target);<a name="line.86"></a>
<span class="sourceLineNo">087</span>    checkNotNull(interfaceType);<a name="line.87"></a>
<span class="sourceLineNo">088</span>    checkNotNull(timeoutUnit);<a name="line.88"></a>
<span class="sourceLineNo">089</span>    checkArgument(timeoutDuration &gt; 0, "bad timeout: " + timeoutDuration);<a name="line.89"></a>
<span class="sourceLineNo">090</span>    checkArgument(interfaceType.isInterface(),<a name="line.90"></a>
<span class="sourceLineNo">091</span>        "interfaceType must be an interface type");<a name="line.91"></a>
<span class="sourceLineNo">092</span><a name="line.92"></a>
<span class="sourceLineNo">093</span>    final Set&lt;Method&gt; interruptibleMethods<a name="line.93"></a>
<span class="sourceLineNo">094</span>        = findInterruptibleMethods(interfaceType);<a name="line.94"></a>
<span class="sourceLineNo">095</span><a name="line.95"></a>
<span class="sourceLineNo">096</span>    InvocationHandler handler = new InvocationHandler() {<a name="line.96"></a>
<span class="sourceLineNo">097</span>      @Override<a name="line.97"></a>
<span class="sourceLineNo">098</span>      public Object invoke(Object obj, final Method method, final Object[] args)<a name="line.98"></a>
<span class="sourceLineNo">099</span>          throws Throwable {<a name="line.99"></a>
<span class="sourceLineNo">100</span>        Callable&lt;Object&gt; callable = new Callable&lt;Object&gt;() {<a name="line.100"></a>
<span class="sourceLineNo">101</span>          @Override<a name="line.101"></a>
<span class="sourceLineNo">102</span>          public Object call() throws Exception {<a name="line.102"></a>
<span class="sourceLineNo">103</span>            try {<a name="line.103"></a>
<span class="sourceLineNo">104</span>              return method.invoke(target, args);<a name="line.104"></a>
<span class="sourceLineNo">105</span>            } catch (InvocationTargetException e) {<a name="line.105"></a>
<span class="sourceLineNo">106</span>              throwCause(e, false);<a name="line.106"></a>
<span class="sourceLineNo">107</span>              throw new AssertionError("can't get here");<a name="line.107"></a>
<span class="sourceLineNo">108</span>            }<a name="line.108"></a>
<span class="sourceLineNo">109</span>          }<a name="line.109"></a>
<span class="sourceLineNo">110</span>        };<a name="line.110"></a>
<span class="sourceLineNo">111</span>        return callWithTimeout(callable, timeoutDuration, timeoutUnit,<a name="line.111"></a>
<span class="sourceLineNo">112</span>            interruptibleMethods.contains(method));<a name="line.112"></a>
<span class="sourceLineNo">113</span>      }<a name="line.113"></a>
<span class="sourceLineNo">114</span>    };<a name="line.114"></a>
<span class="sourceLineNo">115</span>    return newProxy(interfaceType, handler);<a name="line.115"></a>
<span class="sourceLineNo">116</span>  }<a name="line.116"></a>
<span class="sourceLineNo">117</span><a name="line.117"></a>
<span class="sourceLineNo">118</span>  // TODO: should this actually throw only ExecutionException?<a name="line.118"></a>
<span class="sourceLineNo">119</span>  @Override<a name="line.119"></a>
<span class="sourceLineNo">120</span>  public &lt;T&gt; T callWithTimeout(Callable&lt;T&gt; callable, long timeoutDuration,<a name="line.120"></a>
<span class="sourceLineNo">121</span>      TimeUnit timeoutUnit, boolean amInterruptible) throws Exception {<a name="line.121"></a>
<span class="sourceLineNo">122</span>    checkNotNull(callable);<a name="line.122"></a>
<span class="sourceLineNo">123</span>    checkNotNull(timeoutUnit);<a name="line.123"></a>
<span class="sourceLineNo">124</span>    checkArgument(timeoutDuration &gt; 0, "timeout must be positive: %s",<a name="line.124"></a>
<span class="sourceLineNo">125</span>        timeoutDuration);<a name="line.125"></a>
<span class="sourceLineNo">126</span>    Future&lt;T&gt; future = executor.submit(callable);<a name="line.126"></a>
<span class="sourceLineNo">127</span>    try {<a name="line.127"></a>
<span class="sourceLineNo">128</span>      if (amInterruptible) {<a name="line.128"></a>
<span class="sourceLineNo">129</span>        try {<a name="line.129"></a>
<span class="sourceLineNo">130</span>          return future.get(timeoutDuration, timeoutUnit);<a name="line.130"></a>
<span class="sourceLineNo">131</span>        } catch (InterruptedException e) {<a name="line.131"></a>
<span class="sourceLineNo">132</span>          future.cancel(true);<a name="line.132"></a>
<span class="sourceLineNo">133</span>          throw e;<a name="line.133"></a>
<span class="sourceLineNo">134</span>        }<a name="line.134"></a>
<span class="sourceLineNo">135</span>      } else {<a name="line.135"></a>
<span class="sourceLineNo">136</span>        return Uninterruptibles.getUninterruptibly(future, <a name="line.136"></a>
<span class="sourceLineNo">137</span>            timeoutDuration, timeoutUnit);<a name="line.137"></a>
<span class="sourceLineNo">138</span>      }<a name="line.138"></a>
<span class="sourceLineNo">139</span>    } catch (ExecutionException e) {<a name="line.139"></a>
<span class="sourceLineNo">140</span>      throw throwCause(e, true);<a name="line.140"></a>
<span class="sourceLineNo">141</span>    } catch (TimeoutException e) {<a name="line.141"></a>
<span class="sourceLineNo">142</span>      future.cancel(true);<a name="line.142"></a>
<span class="sourceLineNo">143</span>      throw new UncheckedTimeoutException(e);<a name="line.143"></a>
<span class="sourceLineNo">144</span>    }<a name="line.144"></a>
<span class="sourceLineNo">145</span>  }<a name="line.145"></a>
<span class="sourceLineNo">146</span><a name="line.146"></a>
<span class="sourceLineNo">147</span>  private static Exception throwCause(Exception e, boolean combineStackTraces)<a name="line.147"></a>
<span class="sourceLineNo">148</span>      throws Exception {<a name="line.148"></a>
<span class="sourceLineNo">149</span>    Throwable cause = e.getCause();<a name="line.149"></a>
<span class="sourceLineNo">150</span>    if (cause == null) {<a name="line.150"></a>
<span class="sourceLineNo">151</span>      throw e;<a name="line.151"></a>
<span class="sourceLineNo">152</span>    }<a name="line.152"></a>
<span class="sourceLineNo">153</span>    if (combineStackTraces) {<a name="line.153"></a>
<span class="sourceLineNo">154</span>      StackTraceElement[] combined = ObjectArrays.concat(cause.getStackTrace(),<a name="line.154"></a>
<span class="sourceLineNo">155</span>          e.getStackTrace(), StackTraceElement.class);<a name="line.155"></a>
<span class="sourceLineNo">156</span>      cause.setStackTrace(combined);<a name="line.156"></a>
<span class="sourceLineNo">157</span>    }<a name="line.157"></a>
<span class="sourceLineNo">158</span>    if (cause instanceof Exception) {<a name="line.158"></a>
<span class="sourceLineNo">159</span>      throw (Exception) cause;<a name="line.159"></a>
<span class="sourceLineNo">160</span>    }<a name="line.160"></a>
<span class="sourceLineNo">161</span>    if (cause instanceof Error) {<a name="line.161"></a>
<span class="sourceLineNo">162</span>      throw (Error) cause;<a name="line.162"></a>
<span class="sourceLineNo">163</span>    }<a name="line.163"></a>
<span class="sourceLineNo">164</span>    // The cause is a weird kind of Throwable, so throw the outer exception.<a name="line.164"></a>
<span class="sourceLineNo">165</span>    throw e;<a name="line.165"></a>
<span class="sourceLineNo">166</span>  }<a name="line.166"></a>
<span class="sourceLineNo">167</span><a name="line.167"></a>
<span class="sourceLineNo">168</span>  private static Set&lt;Method&gt; findInterruptibleMethods(Class&lt;?&gt; interfaceType) {<a name="line.168"></a>
<span class="sourceLineNo">169</span>    Set&lt;Method&gt; set = Sets.newHashSet();<a name="line.169"></a>
<span class="sourceLineNo">170</span>    for (Method m : interfaceType.getMethods()) {<a name="line.170"></a>
<span class="sourceLineNo">171</span>      if (declaresInterruptedEx(m)) {<a name="line.171"></a>
<span class="sourceLineNo">172</span>        set.add(m);<a name="line.172"></a>
<span class="sourceLineNo">173</span>      }<a name="line.173"></a>
<span class="sourceLineNo">174</span>    }<a name="line.174"></a>
<span class="sourceLineNo">175</span>    return set;<a name="line.175"></a>
<span class="sourceLineNo">176</span>  }<a name="line.176"></a>
<span class="sourceLineNo">177</span><a name="line.177"></a>
<span class="sourceLineNo">178</span>  private static boolean declaresInterruptedEx(Method method) {<a name="line.178"></a>
<span class="sourceLineNo">179</span>    for (Class&lt;?&gt; exType : method.getExceptionTypes()) {<a name="line.179"></a>
<span class="sourceLineNo">180</span>      // debate: == or isAssignableFrom?<a name="line.180"></a>
<span class="sourceLineNo">181</span>      if (exType == InterruptedException.class) {<a name="line.181"></a>
<span class="sourceLineNo">182</span>        return true;<a name="line.182"></a>
<span class="sourceLineNo">183</span>      }<a name="line.183"></a>
<span class="sourceLineNo">184</span>    }<a name="line.184"></a>
<span class="sourceLineNo">185</span>    return false;<a name="line.185"></a>
<span class="sourceLineNo">186</span>  }<a name="line.186"></a>
<span class="sourceLineNo">187</span><a name="line.187"></a>
<span class="sourceLineNo">188</span>  // TODO: replace with version in common.reflect if and when it's open-sourced<a name="line.188"></a>
<span class="sourceLineNo">189</span>  private static &lt;T&gt; T newProxy(<a name="line.189"></a>
<span class="sourceLineNo">190</span>      Class&lt;T&gt; interfaceType, InvocationHandler handler) {<a name="line.190"></a>
<span class="sourceLineNo">191</span>    Object object = Proxy.newProxyInstance(interfaceType.getClassLoader(),<a name="line.191"></a>
<span class="sourceLineNo">192</span>        new Class&lt;?&gt;[] { interfaceType }, handler);<a name="line.192"></a>
<span class="sourceLineNo">193</span>    return interfaceType.cast(object);<a name="line.193"></a>
<span class="sourceLineNo">194</span>  }<a name="line.194"></a>
<span class="sourceLineNo">195</span>}<a name="line.195"></a>




























































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